IDPH Web Site Illinois Behavorial Risk Factor Surveillance System
 BRFSS HOME           
 CONTACT US             
 IDPH Web Site
 IPLAN Data System
Frequently Asked Questions

1. What is the Behavioral Risk Factor Surveillance System (BRFSS)?
BRFSS is the nation's premier system of health-related telephone surveys that collect state data about U.S. residents regarding their health-related risk behaviors, chronic health conditions, and use of preventive services. BRFSS collects data in all 50 states as well as the District of Columbia and three U.S. territories. BRFSS completes more than 400,000 adult interviews each year, making it the largest continuously conducted health survey system in the world. For more information on BRFSS, see this fact sheet[PDF - 1.6 MB](

2. How do you conduct the survey?
With technical and methodological assistance from CDC, state health departments use in-house interviewers or contract with telephone call centers or universities to administer the BRFSS surveys continuously through the year. The states use a standardized core questionnaire, optional modules, and state-added questions. The survey is conducted using Random Digit Dialing (RDD) techniques on both landlines and cell phones. For more information about survey methodology and how it was updated in 2011 to permit use of cell phones for data collection, see Annual Survey Data (

3. What type of information does the BRFSS collect? How often is it collected?
BRFSS collects state data about U.S. residents regarding their health-related risk behaviors and events, chronic health conditions, and use of preventive services. BRFSS also collects data on important emerging health issues such as vaccine shortage and influenza-like illness. For example, since September 2009, federal, state, and local health agencies have used BRFSS to monitor the prevalence rates of influenza-like illness to help with pandemic planning. Interviewers administer the annual BRFSS surveys continuously through the year.

Illinois collects county-specific data over a period of years called Rounds – Illinois County Behavioral Risk Factor Surveys (ICBRFS). With one exception, most rounds collect data from individual counties/county groupings over a three-year period.

4. What is done with this information?
Currently, all states collect BRFSS data to help them establish and track state and local health objectives, plan health programs, implement disease prevention and health promotion activities, and monitor trends. Nearly two thirds of states use BRFSS data to support health-related legislative efforts. In addition, county data is used by Illinois counties for departmental planning.

5. Who takes part in the BRFSS survey? Are they compensated?
Adults 18 years or older are asked to take part in the survey. Participants are not compensated monetarily but should know that they are taking part in a rewarding endeavor that helps improve the health of U.S. residents. The number of interviews within each state will vary based on funding and the size of regions, such as health districts, within each state.

6. Can I download the survey data? Is documentation available?
Survey data and comprehensive documentation (data files, codebooks, design documents, methodology, and more) for a given year can be found in the Annual Survey Data section at

7. What are the components of the BRFSS questionnaire?
The states use a standardized core questionnaire—where some core questions are asked every year (fixed core) and others are asked every other year (rotating core)—optional modules—that states can choose to use according to need—and state-added questions. BRFSS also has included space for as many as four emerging core questions for high-priority topics such as vaccine shortage, and influenza-like illness.

8. How can I find out which states used which optional modules?
Each year states administer the core questionnaire and have the choice to administer optional modules supported by the CDC. To determine which states used which modules, see the Questionnaires ( page.

9. My state asked a question I don't see listed in the questionnaires. Why can't I find it?
Many states include state-added questions at their own expense. Because these questions are not funded by the CDC and are not part of the official BRFSS questionnaire, they are not included on the BRFSS Web site. However, there is a list of state-added question topics available on the BRFSS Questionnaires ( page. For information on state-added questions, contact or look at the questionnaires at

10. How are new questions added to the BRFSS questionnaire?
The content of the BRFSS questionnaire is determined by the BRFSS state coordinators and the CDC. The BRFSS state coordinators may choose to add new questions based on proposals submitted at BRFSS conferences. Each proposal requires a rationale supporting the questions. This rationale should include the following: the origin of the question; history of prior cognitive and validity testing; history of prior use; an analytical plan (i.e., specific prevalence estimates that can be derived from the data); and the extent to which the proposed questions satisfy primary and secondary criteria, such as being pertinent to a Healthy People 2020 objective or priority health issue. The content of the questionnaire reflects the data needs of the state health departments. If questions are approved by the BRFSS state coordinators, then they go through technical review, cognitive testing, and field testing before being placed on the questionnaire.

11. Where can I obtain a copy of the BRFSS questionnaire?
Annual questionnaires dating back to 1984 are available on the BRFSS Web site under BRFSS Questionnaires. Illinois questionnaires are available at the drop-down menu titled Questionnaires on the home page

12. Is the BRFSS questionnaire available in languages other than English?
The questionnaire is also available in Spanish here

13. How are home telephone numbers obtained?
Home telephone numbers are obtained through random-digit dialing (RDD).

14. Do I need to obtain permission to use the BRFSS questionnaire or portions of the questionnaire for my own work? Do I need to obtain permission when publishing or otherwise disseminating graphs and tables based on BRFSS data?
Generally, data and materials produced by federal agencies are in the public domain and may be reproduced without permission. However, we do ask that any published material derived from the data acknowledge CDC's BRFSS as the original source.

Suggested Citation for Survey Questions:
Centers for Disease Control and Prevention (CDC). Behavioral Risk Factor Surveillance System Survey Questionnaire. Atlanta, Georgia: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, [appropriate year].

Suggested Citation for Online BRFSS Database:
Centers for Disease Control and Prevention (CDC). Behavioral Risk Factor Surveillance System Survey Data. Atlanta, Georgia: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, [appropriate year].

Suggested Citation for Illinois BRFSS Databases:
Illinois Department of Public Health (IDPH). Health Statistics. Illinois Behavioral Risk Factor Surveillance Survey (BRFSS) Data. [appropriate year].

Illinois Department of Public Health (IDPH). Health Statistics. Illinois County Behavioral Risk Factor Surveys [appropriate county] [appropriate round].

15. How are BRFSS data weighted? What variables are used when weighting BRFSS data?
From the 1980s to 2010, CDC has used a statistical method called post stratification to weight BRFSS survey data to known proportions of age, race and ethnicity, sex, and geographic region within a population. In 2011 the BRFSS moved to a new weighting methodology known as iterative proportional fitting or raking. Raking has several advantages over post stratification. First, it allows the introduction of more demographic variables—such as education level, marital status, and home ownership—into the statistical weighting process than would have been possible with post stratification. This advantage reduces the potential for bias and increases the representativeness of estimates. Second, raking allows for the incorporation of a now-crucial variable—telephone ownership (landline and/or cellular telephone)—into the BRFSS weighting methodology.

Beginning with the 2011 dataset, raking succeeded post stratification as the BRFSS statistical weighting method. As noted in the previous paragraph, age, sex, categories of ethnicity, geographic regions within states, marital status, education level, home ownership and type of phone ownership are currently used to weight BRFSS data.

16. What methodologic changes have been made to BRFSS?
Methodologic changes were made to the 2011 BRFSS to keep the data accurate and representative of the total population. For information about changes to the 2011 Behavioral Risk Factor Surveillance System, see the

17. What is the SMART BRFSS?
The Selected Metropolitan/Micropolitan Area Risk Trends (SMART) project uses the Behavioral Risk Factor Surveillance System (BRFSS) to analyze the data of selected metropolitan and micropolitan statistical areas (MMSAs) with 500 or more respondents. BRFSS data can be used to identify emerging health problems, establish and track health objectives, and develop and evaluate public health policies and programs. For data, methodology, and other documentation specific to Selected Metropolitan/Micropolitan Area Risk Trends (SMART), please see

18. Are substate area analyses available from the BRFSS?
IDPH has supported the Illinois County Behavioral Risk Factor Surveys since 1996. Individual counties and county groupings are surveyed over a series of 3 to 5 years using the same survey questions and stringent rules as the CDC surveys. The data for these “Rounds” are weighted, analyzed, and distributed to the counties for their use in preparing IPLAN and other reports.

19. What do the asterisks (*) mean when I see them in the data tables?
The data is suppressed if the unweighted cell count is 5 or less and/or row totals 50 or less and/or the confidence interval width is equal to or greater than +/-12.5%. These instances do not meet standards of reliability.

20. I have other questions. Whom should I ask?
All questions should be directed to Illinois BRFSS staff at

For more information about the BRFSS program at CDC, visit that agency's website at